Phytase is an enzyme decomposing phytic acid (myo-inositol 1,2,3,4,5,6 hexakis dihydrogen phosphate) to produce phosphate and phosphate inositol. Phytic acid takes 50˜70% of phosphorus contained in animal feed grains. However, monogastric animals such as fish, fowls and pigs do not have phytase decomposing phytic acid inside body, so that a coefficient of utilization of vegetable phosphorus, which is necessary for growth, is very low, requiring an enough supply from outside body in the form of inorganic compounds. Phytic acid included in feed grains, which is not digested in monogastric animals, can be decomposed enzymatically by microorganisms in soil or in water while it is in transit to the river and the lake. So, the mass-inflow of phosphorus into underwater environment, where only restricted phosphorus is allowed, causes eutrophication inducing a lack of oxygen and a growth of seaweeds. Phytic acid becomes useless after chelating with important trace minerals, amino acids, vitamins, etc, which means it cannot be used in vivo after then, making it an anti-nutrition factor causing a huge nutrition loss in a feed. Thus, if phytase is added to a feed grains for monogastric animals, the useless phytic acid now can be useful, resulting in 1) beneficial reduction of inorganic phosphorus supply, 2) increase of coefficient of utilization of trace bioactive materials, and 3) reduction of phosphorus in animal feces, by which environmental pollution can be reduced. Therefore, the addition of phytase is not only important in economic aspects but also meaningful in environmental protection. Benefits including economic effect of adding phytase are very helpful for preparing globalization.
European countries have been leading the studies on phytase, so far (A. H. J. Ullah, et al., Biochem. Biophys. Res. Commun. 1999, 264, 201-206; K. C. Ehrich, et al., Biochem. Biophys. Res. Commun. 1994, 204(1), 63-68; C. S. Piddington, et al., Gene, 1993, 133(1), 55-62). In particular, they have studied on the effect and functions of phytase extracted from fungi (Aspergillus sp.) in monogastric domestic animals and fish (L. G. Young, et al., J Anim Sci 1993, 71(8), 2147-2150; K. D. Roberson, et al., Poult Sci 1994, 73, 1312-1326; N. Simoes, et al., Reprod Nutr Dev, 1998, 38, 429-440; M. Rodehutscord, et al., Arch Tierernahr 1995, 48, 211-219). However, they had troubles in those studies, for example, the amount of phosphorus digested by phytase was limited, the production of phytase was not economical since it was produced mainly in fungi having a long growth term, and the manipulation was troublesome.
Thus, in order to produce a novel phytase having as excellent activity as or different characteristics from the conventional phytase, the present inventors isolated a novel microorganim producing phytase from thousands of strains gathered from seawater and wastewater treatment plants all over the country and identified thereof. The present inventors completed this invention by confirming that phytase produced by the above microorganism of the invention was a novel protein having a novel base sequence and an excellent titer.